tBeacon UHF Lost Model Beacon Review, Part One

This tiny unit has the potential to aid in the recovery of hundreds, if not thousands of dollars worth of downed equipment. To think it all started with an RCGroups.com user.



tBeacon UHF Lost Model Beacon
Dimensions:0.75x0.98" (19x25mm)
Weight:.088 oz (2.5g)
CPU:Atmega 328P-AU
Power Output:100mW
Transceiver As Tested:Yaesu FT-60
Batteries As Tested:650mAh 3.7V lithium polymer with Team Losi micro connector for initial testing; partially discharged 400mAh 3.7V lithium polymer for the range check
Manufacturer/Available From:tbeacon.org
Price (USD):$50 including shipping through PayPal

If there's one thing I enjoy doing here at RCGroups, it's browsing the blogs to see what other modelers are up to.

A recent entry caught my eye because of its accompanying cartoon; one panel featured a drawing of a handheld amateur radio transceiver announcing the GPS coordinates of a lost model.

As a fairly new addition to the amateur radio ranks, I just had to contact the poster responsible for what would turn out to be a marvelous breakthrough. He's IT engineer and amateur radio operator Konstantin Sbitnev of Chelyabinsk, Russia who posts here at RCG as out0f0rder. Konstantin is the inventor and manufacturer of the tBeacon UHF Lost Model Beacon.

Multirotor users, please take note.

In order to operate, the tBeacon is connected to a model's GPS system and is powered by an ordinary 3.7V lithium polymer battery. Should a model equipped with an tBeacon become lost, the beacon is triggered either by an FM amateur radio transceiver or Family Radio Service transceiver. Once triggered, the tBeacon will transmit its GPS coordinates by voice. It's then a simple matter of following an ordinary handheld GPS navigation unit or even a smartphone with a GPS navigation app to the downed model.

Konstantin was kind enough to forward a sample of the tBeacon to me and I'll be looking at it in two parts. This first part will be a simple overview of how it's operated. The second part will see it hooked up to a GPS system. For those who enjoy soldering their own electronic components, Konstantin offers a DIY circuit board and a list of components needed here.

Getting started is a snap, so let's go!


The tBeacon comes with the following:

  • Fully assembled and tested unit with the buyer's choice of battery connector
  • Cables for connecting to a model's GPS system
  • tBeacon sticker sheet

Needed to complete the system:

  • GPS-equipped model
  • 3.7V lithium polymer battery
  • Multiband or monoband 70cm (440 MHz) FM amateur radio transceiver or Family Radio Service (FRS) transceiver capable of sending a standard 1750 Hz T-CALL repeater actuation tone
  • Portable GPS navigation unit or smartphone with a GPS navigation app
  • Programming software, downloadable from tbeacon.org
  • Programming cable, available from tBeacon.org

My first impression of the tiny tBeacon was incredibly positive. It looked for all the world like a mass-produced unit with its custom etched and printed PC board and surface mounted electronics. Konstantin offers the beacon with the buyer's choice of connectors for the external 3.7V li-po battery needed to power the unit. I have a number of small, 3.7V quadcopters fitted with Team Losi micro connectors and that's what Konstantin offered to install on my sample.

Two sets of micro cables with JST-SH and Dupont connectors are provided as well for easy plug-in connection to the GPS system. The tBeacon is presently compatible with Naza, APM via either GPS or MavLink, Eagle Tree GPS, OpenPilot Revolution and FeiYuTech GPS. Connections to the different systems may be found here.

I'd like to point out that a lot of inexpensive, Chinese-made, handheld amateur transceivers are on the market, some as low as around US$40. I have such a unit, in fact. I bought it from a friend who'd purchased it for use in private event security, not knowing it was an amateur transceiver. It's a popular Baofeng UV-5R, now sold under the Pofung brand name.

That said, one must possess a valid amateur radio license in order to operate any ham radio rig, even the inexpensive ones. Here in the US, the Federal Communications Commission takes a dim view of unlicensed operators and steep fines are a real possibility.

That's the beauty of the tBeacon.

Not everyone who would benefit necessarily possesses a ham radio license. So, the tBeacon can be programmed via computer to operate on frequencies in the FRS band, requiring no license at all. Best of all, FRS radios are inexpensive as well. They're also useful at theme parks, while camping, etc.

Assembly and Setup

No assembly of the tBeacon is required, but it will need to be connected to the model's GPS system per the link above.

Next, the radio used to trigger the system must be programmed. The tBeacon's default operating frequency is 433.075 MHz, an amateur radio UHF frequency. Again, this may be changed via the downloadable software from tBeacon. In fact, I would venture to say that it must be changed to an FRS frequency if one doesn't hold a ham license.

Here in the US, few if any repeater systems use the 1750 Hz tone often used to trigger repeaters in Europe. My radio is programmed to access the local CTCSS or "Continuous Tone-Coded Squelch System" repeaters, but it was a simple matter to turn on the manually operated 1750 Hz function. CTCSS uses sub-audible tones of different frequencies to activate a repeater when a transmitter is keyed; the choice of frequencies is pretty much up to the repeater's owner.

The radio I used for these initial tests was my Yaesu FT-60 dual-band FM transceiver. I have a great time here in my area using that HT ("handie-talkie" for non-hams) to chat on both local repeaters and area-wide IRLP-linked UHF systems such as the PAPA System. It's far easier to program than the Baofeng, but that popular little radio can be programmed to transmit the tone either via the keypad or though a USB cable available through a number of sources including Amazon and eBay. Free software for the ease of programming many popular transceivers is available from the open source CHIRP Project.


Once the tone function was activated, I manually set the radio to 433.075 MHz and plugged in the battery I'd charged for a recent review subject, the JJRC H9D quadcopter. When the battery is plugged in, the tBeacon takes only a moment to initialize. Unlike a repeater, the tBeacon operates in simplex mode, that is, transmission and reception on the same frequency. Most repeaters utilize a duplex mode, in most cases a 6 KHz frequency shift either up or down from the reception frequency when transmitting, but I digress.

To my delight, the tBeacon responded as in the video below with a confirmation tone. Five seconds later, with colored LEDs flashing in unison, a voice announced the battery voltage as "FOUR-TWO," or 4.2 volts. It's a slightly raspy male voice with a bit of an Australian accent. Easy to understand, but Konstantin is working on a beta test of a new voice program as this review goes to press.

Next came the tone test. The tBeacon requires a tone transmission of about three seconds. On the Yaesu FT-60, that's as easy as holding the MONI/T-CALL button on its left side; the radio transmits the tone without the need to press the push-to-talk button.

In a moment, the tBeacon responded once more with high, medium and low tones and the Aussie fellow announcing "ZERO-ZERO-ZERO." Naturally, the zeroes were because I hadn't connected the unit to a GPS system.

The tBeacon transmitted both tones and voice three times each in five-second intervals. To restart the sequence, all I had to do was to push the tone button.

Just too cool.

Range Check

I might not have had a GPS unit at the ready, but that didn't mean I wasn't able to test how well this beacon transmits and receives.

First, in went a partially discharged li-po. "FOUR-ZERO" from the Yaesu.

Next, I turned the transmit power on the Yaesu from its high of 5W to its low of 0.5W, screwed on the stock antenna and I moved the tBeacon to the rear of the house. That's still plenty of power when one considers that any full range 2.4 GHz R/C radio system transmits a mere 100mW.

Then, I went for a stroll.

I thought the structure of the house might block the signal, so I was out the front door and into the courtyard. Nope. Clear signal, full quieting.

Down to the end of the driveway. Same thing.

OK, now I was really determined. I started walking down the street, got about three houses down and keyed the T-CALL once more:


Down to nearly the end of the block:


I heard only a small bit of static this time, so I held the radio higher, tried again and once more, full quieting.

Amazing. Just amazing. I put the tBeacon through the toughest test which I was able to perform under the circumstances and it not only passed, it more than exceeded my expectations. A further check of the specs on the tBeacon discussion page showed this little device's output to be a full 100mW, again, the same as a full-powered, non-amateur R/C transmitter.

Konstantin told me in our correspondence that he'd range tested a tBeacon from the center of his city at a range of 3km, or 1.8 miles.

The result was successful two-way contact with the test unit. He said the signal was scratchy but audible. Given the urban environment, that's simply incredible.

This is one fantastic feat of electronic engineering, friends.

Is This For a Beginner?

Yes! In fact, this is an excellent bit of insurance for those just entering the world of GPS, myself included.

It's exceptionally simple to operate as demonstrated here:

tBeacon quick demo (0 min 45 sec)


This is a no-brainer: If one has a GPS-equipped model, one needs a tBeacon UHF Lost Model Beacon. There are stories galore about flyaway quadcopters, never to be seen again. How many, I wonder, might have been recovered had they been equipped with one of these little jewels?

Given that the tBeacon may be interfaced with a Naza GPS system, I would say the odds are really good that many of these devices will find their ways aboard the DJI Phantom.

Will it fit? Yes, indeed. Konstantin's own photos show just how well:

Based on my initial assessment, this cool little gadget gets two thumbs way, way up.

The next step is to put it to work in a real world situation. As soon as I can arrange to get the tBeacon hooked up to a GPS system, I'll leave a comment and alert our readers to the second part of this review. I'll also arrange to get a programming cable from Konstantin and to talk about the programming aspect of operating the tBeacon. I plan to do a far more intense range check as well.

To be perfectly honest, I'm really looking forward to this!

Many, many thanks to inventor Konstantin Sbitnev. Konstantin told me that he's in the beta phase of some new software and firmware. Among the upgrades are the aforementioned clearer voice prompt, CTCSS operation and the ability to trigger either a buzzer or light for close proximity searches.

Angela Haglund and Jim T. Graham of RCGroups.com make all of these reviews possible for our vast worldwide audience. Thanks for visiting the internet's biggest hobby related discussion site!

Pluses and Minuses

Pluses include:

  • Outstanding sensitivity and transmission range
  • Weighs practically nothing
  • Is powered by a simple battery which most hobbyists might already have on hand
  • Buyers can either get a fully assembled unit or get the board and components for a DIY build
  • Works with either an amateur radio or FRS transceiver
  • Rescue and recovery of just one downed model might well pay for the unit a hundredfold if it were to aid in recovering a professional camera rig
  • The perfect addition to any GPS equipped model

No minuses were noted.

Last edited by DismayingObservation; Mar 18, 2015 at 09:27 PM..
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Mar 27, 2015, 02:53 PM
Registered User
Amazing stuff. Its a great back up incase one does't DVR from the ground station with the GPS co-ordinates displayed via OSD. Also good incase video system/link fails.

Question, does this product function if the flight battery gets disconected? What's powering the GPS? I think this board would be better if it had its own onboard GPS chip, make this a standalone.

I recollect seing a post of a guy selling really small GPS units, our cell phones have a small GPS units don't they?
Mar 27, 2015, 04:00 PM
Registered User
What about interference with uhf rc links? Or does it only transmit when activated?
Mar 27, 2015, 04:52 PM
JulietKiloMike's Avatar
Congrats OutofOrder! Ya made the big time (an RCGroups review...wow!)

Great review, by the way! One thing I might add is that if you can't make out the unit's GPS coordinates due to static, or if you are close enough to the unit that GPS coordinates aren't helping much, it also seems like it would make a great radio direction finder. Just hold your radio receiver close to your chest and rotate until you hear the loudest static / softest signal. The beacon should be right behind you You can also shield your antenna with aluminum foil or take it off the radio to further reduce signal strength (but don't transmit with the antenna off! You'll fry your radio

Mar 27, 2015, 05:28 PM
Pronoun trouble...
DismayingObservation's Avatar
Thread OP
Thanks, gentlemen! Just to clarify the first two posts, the unit is powered by a separate battery and only transmits when activated.

Thanks and 73s for the tip, John!

By the way, I tried it with another ham at a distance of about 3/4 of a mile. I was in an industrial park, she was at home and a whole lot of buildings were between her and I. Worked like a charm. Amazing little device.
Mar 27, 2015, 05:35 PM
Registered User
I get that the unit is self powered. But what good is a self powered unit if the flight pack disconnects and the GPS receiver looses power?
Maybe this device can constantly store the last position therefore it can send out the last known position when asked.
Mar 27, 2015, 06:57 PM
Pronoun trouble...
DismayingObservation's Avatar
Thread OP
You know, that's an excellent question...

I'd check with Konstantin about that. I'll try my unit with and without the flight battery when I hook it up to a GPS system. I'm guessing that it would have to be an incredibly severe crash to disconnect the flight battery, so perhaps it doesn't have the capability. At least it might not just yet.
Last edited by DismayingObservation; Mar 27, 2015 at 07:04 PM.
Mar 27, 2015, 07:49 PM
JulietKiloMike's Avatar
Originally Posted by DismayingObservation
Thanks, gentlemen! Just to clarify the first two posts, the unit is powered by a separate battery and only transmits when activated.

Thanks and 73s for the tip, John!

By the way, I tried it with another ham at a distance of about 3/4 of a mile. I was in an industrial park, she was at home and a whole lot of buildings were between her and I. Worked like a charm. Amazing little device.
Originally Posted by RyanFromYEG
I get that the unit is self powered. But what good is a self powered unit if the flight pack disconnects and the GPS receiver looses power?
Maybe this device can constantly store the last position therefore it can send out the last known position when asked.
Radio direction finding is more powerful than you might think! As long as you can pick up the signal from the transmitter, you should be able to track it down using RDF. In urban environments the signal reflections can be a bit tricky, but it'll work even if you don't have GPS coordinates...think of it as a miniature foxhunt transmitter for your airplane! You should still be able to find it from miles away.

I posted on the original tBeacon blog entry about adding a morse code callsign ident feature, and OutOfOrder said he had memory constraints on the unit, so storing a large GPS history might be out of the question, but I think it would be pretty easy to add a filtering algorithm that rejected "null" GPS data (ie. when the NMEA string indicates that there isn't a lock) and kept the old data instead. The only problem would be that it would become hard to tell when the GPS is working and when the unit is just sending old data.

Last edited by JulietKiloMike; Mar 27, 2015 at 10:54 PM.
Mar 27, 2015, 10:48 PM
out0f0rder's Avatar
Thanks Ralph! The review is amazing!
Just can't express my feeling how awesome to get such warm reception

OK guys, answering your questions.

Regarding broken GPS connection: of course it is envisioned. Locations is filtered and saved in RAM. That is: it is retains as long as autonomous power supply is OK.
In the next release location is saved to non-volatile memory and retains across poweroff. As a bonus you'll get a simple GPS-tracker which could show a part of your model's path
By the way, there is a bunch of neat features getting ready for release. Morse code mentioned by John is only one of them. And sure enough the next release is fully compatible with the current hardware.

Regarding autonomous GPS: of course you are able to attach almost any commercial GPS receiver. The only trouble is power supply: GPS receivers are very power hungry
That's why I still don't have a complete solution. Maybe sometime.

Thanks to Ralph and Jonh for explanation on interference and RDF.

Do not hesitate to ask any question, I'll be glad to answer all of them

Last edited by out0f0rder; Mar 28, 2015 at 01:30 AM.
Mar 28, 2015, 12:22 AM
Pronoun trouble...
DismayingObservation's Avatar
Thread OP
Konstantin, believe me, it was my pleasure. I'll get my sample hooked up to a GPS unit soon. The other ham who helped me with the range check is president of one of the local clubs and she was incredibly impressed. In fact, I didn't have to trigger the beacon! We were talking simplex on 433.075 and her voice hit just the right pitch.

I'm also going to suggest that the tBeacon be featured on Amateur Radio Newsline at www.arnewsline.org. That weekly newscast is heard via amateur radio and a few broadcast stations all over the world. I think it's worth a story.

PS: An email has just been sent. I'll be in touch.
Mar 28, 2015, 01:44 AM
out0f0rder's Avatar
Originally Posted by DismayingObservation
In fact, I didn't have to trigger the beacon! We were talking simplex on 433.075 and her voice hit just the right pitch.
Yep, 1750Hz is in human voice frequency range. Technically you can sing a calling tone
Actually you are lucky guy: it is very unlikely event. During my tremendous amount of testing I encountered false triggering only once.
But I prefer choosing not so busy channels
Mar 28, 2015, 10:56 AM
Registered User
wkf94025's Avatar

Impressive product. I'm in.

Please spec what I need for use on my Phantom 2's and also on various gliders running Eagle Tree Vector. I don't mind soldering a few wires here and there, but also enjoy good plug-n-play installs. I will likely use a basic FRS radio. I sometimes fly beyond cell coverage, and sometimes in Mexico, where I can't rely on cell coverage, global data roaming, etc. for my Flytrex Live 3G system on the Phantoms, or DVR of Vector OSD for last known location.

What's your schedule for implementing NVRAM storage of last "good" GPS location?


PS: Ralph, thanks for a comprehensive and professional review.
Mar 28, 2015, 01:25 PM
out0f0rder's Avatar
Originally Posted by wkf94025
Please spec what I need for use on my Phantom 2's and also on various gliders running Eagle Tree Vector.
It's pretty easy with Phantom cause it's just Naza inside. You have to make an adaptor like this one or simply cut and solder three wires.
I think it would be nice to offer ready made adapter for Nazas an Phantoms but I'm just not ready for this.
Regarding Vector: hardcore soldering required.
EagleTree folks promised to provide open telemetry on a dedicated port, but at the moment it is only done for FrSky telemetry, which I'm unable to parse
So you have to open the GPS box and solder directly to GPS module. I will provide some photos and instructions later.
BTW, I use tBeacon with the Vector on my Tarot FY680 hexa.

Originally Posted by wkf94025
What's your schedule for implementing NVRAM storage of last "good" GPS location?
It is implemented already But I have to test it thoroughly, write docs, hints, etc before release.
I hope to release it in a couple of weeks.
Mar 28, 2015, 03:30 PM
Registered User
stanordave's Avatar
I just ordered one!

..then I read this thread..and saw about the planned changes..which I really want..

guess I'll have to get another after they've been implemented
Mar 28, 2015, 07:32 PM
Happy Holidays
AnthonysQuad's Avatar
I might order one but i have to get my quad repaired first.Its awalys nice seeing new thing.Its also nice seeing people from diffent countrys working together.Something are idiot leaders cant figure out.

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